External jobs do not have show page nor traces

Fixes #24677

app/views/notify/pipeline_failed_email.html.haml

@@ -158,12 +158,20 @@
                                             %td{style: "font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;color:#8c8c8c;font-weight:500;font-size:15px;vertical-align:middle;"}
                                               = build.stage
                                     %td{align: "right", style: "font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;padding:20px 0;color:#8c8c8c;font-weight:500;font-size:15px;"}
-                                      %a{href: pipeline_build_url(@pipeline, build), style: "color:#3777b0;text-decoration:none;"}
+                                      - case build
+                                      - when Ci::Build
+                                        %a{href: pipeline_build_url(@pipeline, build), style: "color:#3777b0;text-decoration:none;"}
+                                          = build.name
+                                      - when GenericCommitStatus
                                         = build.name
                                   %tr.build-log
-                                    %td{colspan: "2", style: "font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;padding:0 0 15px;"}
-                                      %pre{style: "font-family:Monaco,'Lucida Console','Courier New',Courier,monospace;background-color:#fafafa;border-radius:3px;overflow:hidden;white-space:pre-wrap;word-break:break-all;font-size:13px;line-height:1.4;padding:12px;color:#333333;margin:0;"}
-                                        = build.trace_html(last_lines: 10).html_safe
+                                    - case build
+                                    - when Ci::Build
+                                      %td{colspan: "2", style: "font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;padding:0 0 15px;"}
+                                        %pre{style: "font-family:Monaco,'Lucida Console','Courier New',Courier,monospace;background-color:#fafafa;border-radius:3px;overflow:hidden;white-space:pre-wrap;word-break:break-all;font-size:13px;line-height:1.4;padding:12px;color:#333333;margin:0;"}
+                                          = build.trace_html(last_lines: 10).html_safe
+                                    - when GenericCommitStatus
+                                      %td{colspan: "2"}
         %tr.footer
           %td{style: "font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;padding:25px 0;font-size:13px;line-height:1.6;color:#5c5c5c;"}
             %img{alt: "GitLab", height: "33", src: image_url('mailers/ci_pipeline_notif_v1/gitlab-logo-full-horizontal.gif'), style: "display:block;margin:0 auto 1em;", width: "90"}/

app/views/notify/pipeline_failed_email.text.erb

@@ -19,10 +19,12 @@ Commit Author: <%= commit.author_name %>
 Pipeline #<%= @pipeline.id %> ( <%= pipeline_url(@pipeline) %> ) had <%= failed.size %> failed <%= 'build'.pluralize(failed.size) %>.
 <% failed.each do |build| -%>
-Build #<%= build.id %> ( <%= pipeline_build_url(@pipeline, build) %> )
+Build #<%= build.id %><%= if build.kind_of?(Ci::Build) then " ( #{pipeline_build_url(@pipeline, build)} )" end %>
 Stage: <%= build.stage %>
 Name: <%= build.name %>
+<% if build.kind_of?(Ci::Build) -%>
 Trace: <%= build.trace_with_state(last_lines: 10)[:text] %>
+<% end -%>
 <% end -%>

spec/models/ci/pipeline_spec.rb

@@ -571,7 +571,13 @@ describe Ci::Pipeline, models: true do
     context 'with failed pipeline' do
       before do
         perform_enqueued_jobs do
-          pipeline.drop
+          create(:ci_build, :created, pipeline: pipeline)
+          create(:generic_commit_status, :created, pipeline: pipeline)
+
+          pipeline.statuses.count.times do |offset|
+            # workaround race conditions
+            pipeline.statuses.offset(offset).first.drop
+          end
         end
       end